OK. An A level in England is a single two-year course. Taking an AS level in the same subject (which is an entirety separate qualification in England) would be very usual.
Did you take formal external AS exams, marked by an exam board, and with the resulting grade being issued by an exam board? Or were the papers set and marked by your school, just like end-of-year exams?
Also, you use the word "fail". Does that mean a U grade, or just a grade you were disappointed with?